This article will take you through the possible reasons for a “timeout/connection refused” root cause on an uptime test:

• A connection refusal may occur due to trying to access a website in an unauthorized fashion, through a closed port, or because of security restrictions from a Firewall.
• In the case that a site is taking a long time to load, we will wait a maximum of 75 seconds before marking a timeout, this timing can be lowered by modifying the Crawl Timeout setting on the test.
• DNS settings might fluctuate based on the provider. Its always worth checking the status of the DNS provider, or if you use any WAF (like cloudflare) there could be intermittent issues over time where visitors fail to get a connection.
• The maximum number of connections enabled on the target server might have an impact, where the server has reached it’s connection limit as a result of normal visitors, as well as connections from any bots